“We’ve been going through a massive thought evolution and many taboos have been broken,” Diaz-Canel said.

Cuban citizens will vote on the issue in a national referendum in February 2019.

Cuba currently operates under its 1976 national charter, which defines marriage as a “voluntary union of a man and a woman.” In the proposed constitution, which was approved by the Cuban parliament in June, new language was added to define marriage as a union between “two people.”

The shift in the Cuban leadership’s attitude toward same-sex marriage is largely attributed to the efforts of Mariela Castro, the daughter of former Cuban president Raul Castro.

As the director of the Cuban National Center for Sex Education, the younger Castro received international support for condemning homophobic attacks in Cuba and advocating for same-sex marriage.